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Worksheet: Converting Concentrations to pH and pOH

Q1:

What is the pOH of a 0.0125 M solution of potassium hydroxide, K O H ?

  • A0.0125
  • B12.1
  • C9.99
  • D1.90
  • E4.01

Q2:

To 1 decimal place, what is the pH of 0 . 0 0 3 1 M C a ( O H ) 2 at 2 5 ∘ C ? Assume that C a ( O H ) 2 ionizes completely.

Q3:

To 1 decimal place, what is the pH of 2 . 5 M K O H at 2 5 ∘ C ? Assume that K O H ionizes completely.

Q4:

To 2 decimal places, what is the pH of 0 . 0 1 4 3 M N a O H at 2 5 ∘ C ? Assume that N a O H ionizes completely.

Q5:

Calculate to 3 significant figures the hydroxide concentration of a solution with a pH of 6.52 at 2 5 ∘ C . The self-ionization constant of water, 𝐾 w , is 1 . 0 0 Γ— 1 0 βˆ’ 1 4 at this temperature.

  • A 5 . 0 6 Γ— 1 0 βˆ’ 7 M
  • B 3 . 0 1 Γ— 1 0 βˆ’ 7 M
  • C 6 . 7 9 Γ— 1 0 βˆ’ 9 M
  • D 3 . 3 1 Γ— 1 0 βˆ’ 8 M
  • E 8 . 9 5 Γ— 1 0 βˆ’ 9 M

Q6:

To 2 decimal places, what is the pOH of 0 . 0 1 4 3 M N a O H at 2 5 ∘ C ? Assume that N a O H ionizes completely.

Q7:

To 2 decimal places, what is the pOH of 0 . 2 1 M N a O H at 2 5 ∘ C ? Assume that N a O H ionizes completely.

Q8:

To 1 decimal place, what is the pOH of a 0.000259 M aqueous H C l O 4 solution at 2 5 ∘ C ? Assume that H C l O 4 is completely ionized.

Q9:

To 2 decimal places, what is the pH of 0 . 0 0 0 0 7 1 M B a ( O H ) 2 at 2 5 ∘ C ? Assume that B a ( O H ) 2 ionizes completely.

Q10:

What is the pOH of 0 . 0 0 3 1 M C a ( O H ) 2 at 2 5 ∘ C ? Assume that C a ( O H ) 2 ionizes completely.

  • A2.5
  • B11.8
  • C11.5
  • D2.2
  • E1.7

Q11:

What is the pH of a 0.0125 M solution of potassium hydroxide, K O H ?

  • A0.0125
  • B1.90
  • C9.99
  • D12.1
  • E4.01

Q12:

To 2 decimal places, what is the pOH of 2 . 5 M K O H at 2 5 ∘ C ? Assume that K O H ionizes completely.

Q13:

To 1 decimal place, what is the pOH of 3 . 0 M H N O 3 at 2 5 ∘ C ? Assume that H N O 3 ionizes completely.

Q14:

To 2 decimal places, what is the pOH of 0 . 0 0 0 0 7 1 M B a ( O H ) 2 at 2 5 ∘ C ? Assume that B a ( O H ) 2 ionizes completely.

Q15:

The p O H of the conjugate base of an unknown aqueous acid is 4.17. What is the H + concentration of the unknown acid?

  • A 6 . 7 6 Γ— 1 0 βˆ’ 5 M
  • B 2 . 2 7 Γ— 1 0 βˆ’ 1 2 M
  • C 4 . 6 6 Γ— 1 0 βˆ’ 2 M
  • D 1 . 4 8 Γ— 1 0 βˆ’ 1 0 M

Q16:

Coffee has a pH of about 5.1. Calculate to 2 significant figures the hydroxide ion concentration of coffee at 2 5 ∘ C .

  • A 6 . 3 Γ— 1 0 βˆ’ 1 1 M
  • B 7 . 9 Γ— 1 0 βˆ’ 6 M
  • C 1 . 6 Γ— 1 0 βˆ’ 1 8 M
  • D 1 . 3 Γ— 1 0 βˆ’ 9 M
  • E 1 . 2 Γ— 1 0 βˆ’ 1 2 M

Q17:

The hydronium ion concentration of vinegar is approximately 4 . 0 Γ— 1 0 βˆ’ 3 M. What is the corresponding value of the pOH?

  • A 4 Γ— 1 0 βˆ’ 3
  • B2.4
  • C1.0
  • D12
  • E13

Q18:

To 1 decimal place, what is the pH of 0 . 2 1 M N a O H at 2 5 ∘ C ? Assume that N a O H ionizes completely.